Dennis Tanner is a fictional character from the British ITV soap opera Coronation Street, played by Philip Lowrie. The character was created by writer Tony Warren and was introduced in the first episode on 9 December 1960. Lowrie remained in the role for just over a year before being written out unexpectedly in 1962 when a strike by the actor's union Equity prevented new contracts being signed. Although the strike ended a few months later, Lowrie chose not to return until a year later. After a further five years, Lowrie became frustrated with the material his character was getting and decided not to renew his contract. Dennis departed Coronation Street on 12 June 1968, shortly after marrying girlfriend Jenny Sutton.

It was announced in January 2011 that the character would be returning to the soap once again after a 43-year absence. His return made it the longest any actor in Coronation Street has taken a break. His return aired on 12 May 2011.

In September 2011, Lowrie was presented with a certificate by Guinness World Records for being the person with the longest gap between television appearances in the same show, having returned to Coronation Street as Dennis Tanner.

It was announced on 14 December 2013 that Lowrie was to leave Coronation Street. He departed, alongside co-star Sue Johnston, who plays Gloria Price, on 21 February 2014. Dennis returned again briefly for another storyline from April to July 2014.

It was announced in February 2020 to mark the soap's 10,000th episode that Dennis Tanner was killed off-screen.

Introduced as a teenage tearaway, Dennis quickly became a reformed character and for most of his time on the show, he was primarily used as the show's comic relief with his storylines revolving around his interest in show business, much to the annoyance of his mother Elsie (Pat Phoenix). Dennis was later described as "immensely popular".

Dennis was one of the original characters created by Tony Warren when devising his new serial, then named Florizel Street. Warren had envisaged Dennis as the show's bad boy, and was initially attracted to the idea of casting himself in the role. Warren explained "It was a much better part than Ken, as originally written. There were infinite possibilities in Dennis that were never explored. The criminal side. In those streets there is always a bad 'un, a wrong 'un. And he was the wrong 'un." Producers auditioned several actors for the part, of which two were picked to play Dennis in the pilots. Both proved to be unsuitable and Dennis was one of the last characters to be cast. Eventually it was down to two actors, Ken Farrington and Philip Lowrie, who were called in for camera tests opposite Pat Phoenix, who was cast already as Dennis' mother. Lowrie was chosen to play Dennis just days before rehearsals began, while Farrington was assured that despite not getting the part of Dennis, they wanted him to play another character due to be introduced later in the series, which turned out to be Billy Walker.

Lowrie remained in the series until he was written out in 1962, due to a strike at the time which prevented him from signing a new contract. Since his contract was just slightly longer than most of his peers, it meant Dennis' exit was timed a little later than the other cast members who had to leave because of the strike. Lowrie had wanted to leave with his screen sister Anne Cunningham, who played Linda, at the end of 1961 but producers vetoed the idea as they did not want all of Elsie's family deserting her at the same time. Lowrie returned to Coronation Street in 1963, and remained for a further five years, before tiring of the role and handing in his notice in 1968. In 2011, forty-three years after his last appearance, it was announced Dennis was to return to the Street, after Philip Lowrie agreed to reprise the role. His return made it the longest any actor in Coronation Street has taken a break.